People experience what they consider elevated states of mind when they go out to the wilderness or are in a geographic location that allows them to be more physically closer to nature, and further away from the city. This, of course, has scientific reasoning behind it. In the forest and further away from the city, the amount of carbon monoxide and sulfur dioxide decreases significantly simply because of having more trees around. Forests are further away from car pollutants and other pollution in factories in general. However, a study conducted to measure the effect of trees within cities revealed that they reduced pollutants such as carbon monoxide and sulfur dioxide as well. “In park areas with 100% tree cover (i.e., contiguous forest stands), air pollution improvements average around 4 times greater than city averages with short-term improvements in air quality (one hour) as high as 16% for ozone and sulfur dioxide, 13% for particulate matter, 8% for nitrogen dioxide, and 0.05% for carbon monoxide” (Nowak et al., 2010). With this study in mind, trees clearly contribute to the reduction of pollution in forests, despite the potential for a confounding variable such as distance from the city.
In another study conducted to measure the effects of carbon monoxide on serotonin levels, rats were exposed to 6000 PPM of carbon monoxide for 3 intervals of 10 minutes. Afterwards, these findings indicated that CO exposure caused presynaptic serotonergic neuronal dysfunctions that consisted mainly of decreased concentration of 5-HT in the frontal cortex or a decrease of 5-HT synthesis in all six regions of the brain. These dysfunctions happened without compensatory hyperfunction of 5-HT2A hyperfunction of 5-HT2A receptors (Muroka et al., 1998) To put this into simpler terms, decreased concentration of 5-HT in the frontal cortex leads to various psychiatric disorders, such as schizophrenia and depression. (Puit et al., 2011).
With this in mind, it is important to note that pollutants in the air do have a neural effect on individuals, which can influence their behavior. The behavior can be displayed through depression or aggression, which are neither indicators of a healhty state of mind.